When a long-distance meeting is needed, people are increasingly accustomed to using video conferencing, which can achieve good communication. However, during the video conferencing, participants may not accurately understand the meaning expressed by speakers or misjudge what is being said. For example, when a presentation needs to be shared, although each participant in any place can see content of the presentation, the speaker can only verbally indicate the location of some argument or point in the presentation, even using a laser pen may not be clear enough, so the participants will not really understand the briefing or flow of ideas expressed by the speaker.